What is Alumina?

Alumina (Al2O3), otherwise known as aluminum oxide, is an advanced refractory belonging to the oxide group of technical ceramics. It is an extremely versatile material that can be bonded and formed using a broad range of consolidation and sintering techniques, yielding precise near-net shapes in a range of purities.

The purity of the ceramic (i.e. the concentration of alumina to additive agents) tends to be the defining factor in characterizing distinct grades, with higher purities typically corresponding to greater strength, corrosion- and wear-resistant properties. Such is the case with International Syalons’ Aluminon range of alumina ceramics:

  • Aluminon 96 (96% Al2O3)
  • Aluminon 995 (99.5% Al2O3)
  • Aluminon 999 (99.6% Al2O3)

In this blog post, we will outline the properties and applications of alumina ceramics in more detail.

Alumina refractory insulators

Material Properties of Alumina

Alumina is a well-balanced ceramic derived from the polymorphic alpha- (α-) phase mineral corundum, sharing the crystalline structures of sapphire and ruby: Al2O3. Consequently, it is one of the hardest engineered ceramics; second only to silicon carbide (SiC). This high hardness is accompanied by outstanding resistance to abrasion and wearing, excellent thermal conductivity, and superb resistance to chemical attack.

Refer to the table below for more information on the material properties of our alumina product range:


Property Aluminon 96 Aluminon 995 Aluminon 999
Vickers Hardness

15.71 GPa (Kg/mm2)

15.71 GPa (Kg/mm2)

17.65 GPa (Kg/mm2)

Fracture Toughness

3.5 MPa m½

4.0 MPa m½

4.5 MPa m½

Compressive Strength

>2000 MPa

>2000 MPa

>2500 MPa

Thermal Shock Resistance

ΔT = 200°C

ΔT = 200°C

ΔT = 220°C

Thermal Conductivity

20.0 W/(mK)

30.0 W/(mK)

30.0 W/(mK)


Applications of Alumina

This outstanding compound of properties makes alumina uniquely suited for an extremely wide range of application areas. With high hardness and wear-resistant properties, it is often utilized in mining and material transfer components in earthmoving and exploration. These mechanical properties have also proven beneficial in armour plating applications, for military vehicles and personnel. Alumina is also widely utilized in high-temperature and corrosive processing environments, including kilns and furnaces on challenging production lines.

Learn more in A Guide to Technical Ceramics

International Syalons’ Aluminon product line is extremely high-purity, providing superior corrosion- and wear-resistant properties for demanding processing environments. Our robust alumina products are particularly well suited for challenging oil and gas applications.

Aluminon Products from International Syalons

International Syalons is one of the UK’s leading suppliers of advanced ceramics, offering a versatile line of ceramics under the Aluminon brand name. If you would like more information about our full range of advanced ceramics, please do not hesitate to contact a member of the International Syalons team today.

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